JP2002037512A - Sheet post-processing apparatus and image forming apparatus equipped with this apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the consistency of an end portion of a sheet in a conveying direction. A sheet post-processing device includes a receiving unit that receives an upstream end of a sheet stacked on a stacking unit in a conveying direction, and a first conveyance alignment that conveys the sheet on the stacking unit toward the receiving unit. Means 71 and matching means 71
The second transport aligning means 19 which transports the sheet and makes contact with the sheet receiving means to align the upstream end of the sheet.
Controlling the width of the sheet bundle stacked on the stacking means in a direction intersecting the sheet conveying direction, and controlling the first and second conveyance aligning means of the sheet discharged on the stacking means. Then, the sheet is brought into contact with the receiving means to align the end of the sheet in the conveying direction, the operation of the width adjusting means is controlled to adjust the width of the sheet, and the operation of the first conveying aligning means is controlled again to receive the sheet. Control means for abutting the end of the sheet in the conveying direction by contacting the end means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet post-processing apparatus for aligning sheets, and an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction machine having the sheet post-processing apparatus. .

[0002]

2. Description of the Related Art Conventionally, a sheet post-processing apparatus that performs a sheet stacking operation for stacking a plurality of discharged sheets and a binding operation (stepping operation) for binding the plurality of sheets has been performed when a sheet bundle is bound. The sheet discharged from the discharge roller onto the staple tray is moved in a direction along the sheet conveying direction to perform the aligning operation, align the edges in the sheet conveying direction, and bind the sheet bundle. For this reason, the sheet post-processing apparatus has an elastic member called a paddle, and an alignment belt that rotates in synchronization with a discharge roller that discharges a sheet onto the staple tray, and a nip point between the alignment belt and the staple tray by the paddle. Back, and then the sheet is abutted against the alignment abutting member by the frictional force of the alignment belt to perform alignment in the transport direction.

Here, since the alignment belt is driven and rotated by the rollers of the discharge roller so as to rotate in synchronization with the discharge roller, the rear end of the sheet is slightly separated from the alignment belt and drops onto the staple tray. Was. In this state, the alignment belt cannot align the ends in the sheet conveyance direction. Therefore, the tray on which the sheets are stacked is inclined so that the sheets slide down toward the alignment belt, and the paddles are forcibly formed. Pulling back in the direction of the alignment belt.

The sheet discharged onto the staple tray and abutted against the alignment abutting member and aligned at the end in the sheet transport direction is further aligned by a width alignment member in a direction intersecting the sheet transport direction. In response to the movement, the width can be aligned.

The sheets include plain paper, resin-made substitutes for plain paper, and cardboard.

[0006]

By the way, the sheet includes a regenerated sheet having an unstable coefficient of friction on the sheet, and a sheet which is easily charged and stuck due to static electricity. In addition, some of these sheets have a length in the sheet conveying direction that is longer than the dimension in the width direction.

Therefore, the conventional sheet post-processing apparatus is
After the above-described sheet discharged onto the staple tray is abutted against the alignment abutting member to align the ends in the sheet conveyance direction, the width alignment member may perform the sheet width alignment operation. However, it has been difficult to maintain the state of alignment with the alignment abutting member and perform parallel movement for alignment.

In addition, due to the size limitation of the sheet post-processing device, the width aligning member of the conventional sheet post-processing device presses only the rear end near the alignment abutting member of the sheets stacked on the staple tray. Since the operation cannot be performed, it is more difficult to move the sheet in parallel with the aligning butting member to align the sheet.

(Purpose) The present invention is directed to, for example, the consistency of the end of the sheet in the conveyance direction of a sheet having a large friction coefficient, a sheet which is easily charged with static electricity, or a sheet having a size longer in the conveyance direction than the width of the sheet. It is an object of the present invention to provide a sheet post-processing apparatus with improved image quality and an image forming apparatus provided with the sheet post-processing apparatus in a main body.

[0010]

In order to achieve the above object, a sheet post-processing apparatus according to the present invention comprises a sheet stacking unit on which discharged sheets are stacked, and a conveyance of the sheet stacked on the sheet stacking unit. Sheet receiving means for receiving the upstream end portion in the direction, first sheet transport aligning means for transporting the sheets stacked on the sheet loading means toward the sheet receiving means, and first sheet transport aligning means. A second sheet transport aligning unit that abuts the transported sheet against the sheet receiving unit to align an upstream end in the transport direction of the sheet, and a sheet bundle stacked on the sheet stacking unit. Sheet width aligning means for aligning in a direction intersecting the conveying direction of
Controlling the operation of the sheet transport aligning means to transport the sheet on the sheet stacking means to the second sheet transport aligning means, and controlling the operation of the second sheet transport aligning means to transfer the sheet to the sheet The end of the sheet in the conveying direction is aligned by contacting the receiving means, and then the width of the sheet is adjusted by controlling the operation of the sheet width aligning means. Control means for controlling the operation to bring the sheet into contact with the sheet receiving means to align the end of the sheet in the conveying direction.

[0011] The control means of the sheet post-processing apparatus of the present invention may be configured such that when the length of the sheet in the conveying direction is equal to or more than a predetermined length, and when the sheet stacking means has stacked the predetermined number of sheets or more. When at least one of the first
The operation of the sheet conveying alignment means is controlled again.

The first sheet conveying and aligning means of the sheet post-processing apparatus of the present invention has an intermittently rotating elastically deformable rotating member.

The second sheet conveying and aligning means of the sheet post-processing apparatus of the present invention has a rotating body which can be elastically deformed.

In the sheet post-processing apparatus according to the present invention, the first sheet transport aligning means has an intermittently rotating elastically deformable rotating member, and the second sheet transport aligning means has an elastically deformable rotating body. The rotating member is disposed above the rotating body.

The rotator of the sheet post-processing apparatus according to the present invention is rotatable in a direction in which the sheet stacked on the sheet stacking means is conveyed away from the sheet receiving means and discharged.

The sheet post-processing apparatus of the present invention further comprises a sheet binding means for binding a sheet bundle stacked on the sheet stacking means.

In order to achieve the above object, an image forming apparatus according to the present invention comprises: an image forming means for forming an image on a sheet; and an image forming means for aligning the sheet on which the image is formed by the image forming means. And a processing device.

(Operation) In the sheet post-processing apparatus, the control means controls the operation of the first sheet conveying and aligning means so that the sheet discharged on the sheet stacking means is controlled by the second sheet conveying and aligning means. Then, the operation of the second sheet conveyance aligning means is controlled to abut the sheet receiving means. As a result, the sheet conveying direction ends are aligned. Next, the control means controls the operation of the sheet width aligning means to adjust the width of the sheet. At this time, if the sheet is a sheet having a large coefficient of friction, a sheet easily charged with static electricity, or a sheet having a longer dimension in the conveying direction than the sheet in the width direction, or if the number of stacked sheets is large, the width adjustment is performed. It is difficult for the set sheet to move in parallel along the sheet receiving means, and the alignment of the end in the sheet conveyance direction may be disturbed. In such a case, the control means controls the operation of the first sheet conveyance alignment means again to bring the sheet into contact with the sheet receiving means, thereby aligning the end of the sheet in the conveyance direction. This allows the sheet to:
The width of the sheet and the end in the conveyance direction are reliably aligned.

When the sheet is difficult to be charged or has a short length, or when the number of stacked sheets is small, the width-aligned sheet easily moves in parallel along the sheet receiving means. The alignment of the ends in the transport direction is less likely to be disturbed. In such a case,
The control means does not operate the first sheet conveyance aligning means again.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the internal configuration of a copying machine as an example of an image forming apparatus. In FIG. 1, reference numeral 1 denotes a main body of a sheet post-processing apparatus 600 according to the embodiment of the present invention, reference numeral 100 denotes a main body of a copying machine (image forming apparatus) 700, and reference numeral 200 denotes a plurality of sheets of different sizes. Reference numeral 300 denotes a document feeder (hereinafter, referred to as an ADF) for automatically feeding a document. Note that the sheet post-processing apparatus 600 can be equipped not only in the main body of the copying machine but also in the main body of another image forming apparatus such as a printer, a facsimile, and a composite device thereof.

In the main body 100 of the copying machine, reference numeral 101 denotes
Reference numeral 103 denotes a platen glass on which a document is loaded.
Numeral 04 denotes a scanning reflection mirror for changing the optical path of reflected light of the original, numeral 105 denotes a lens having a focusing and magnification function, numeral 106 denotes an illumination lamp for reading the original sent from the ADF 300, and Reference numeral 107 denotes a registration roller, reference numerals 108 and 110 denote photosensitive drums and pressure rollers, and reference numeral 111 denotes a transport belt that transports an image-recorded sheet to a fixing side. Reference numeral 112 denotes a fixing device for thermocompressing the conveyed sheet.

Reference numerals 113 and 117 denote transport rollers for transporting the sheet, reference numeral 114 denotes a flapper for switching the transport direction of the transported sheet, and reference numeral 11 denotes a flapper.
Reference numeral 5 denotes a sheet discharge roller for conveying the sheet in the direction of the main body 1 of the sheet post-processing apparatus, reference numeral 116 denotes a reversing path for reversing the front and back of the sheet, and reference numeral 118 denotes a cassette 20.
Reference numeral 119 denotes a transport roller for transporting a sheet from the manual feed unit, reference numeral 120 denotes a manual feed tray, and reference numeral 122 denotes a separation pad.

Reference numerals 122, 123 and 125 denote a laser unit for forming an image on the photosensitive drum, a polygon mirror, and a mirror for changing the optical path. Code 124
Denotes a motor for driving the polygon mirror 123. Reference numeral 200 denotes a cassette in which sheets of each size are stacked by type, and sheets are supplied to the main body by type according to a signal from the main body 100 of the copying machine. Reference numeral 201 denotes a conveying roller for extracting the sheets from the cassette.
Reference numeral 2 denotes an intermediate roller for transferring the sheet drawn from the cassette upward.

The surface of the photosensitive drum 108 is composed of a photoconductor and a seamless photosensitive member using a conductor. The photosensitive drum 108 is rotatably supported and responds to pressing of a copy start key (not shown). The rotation is started in the direction of the arrow in FIG. When the predetermined rotation control and potential control processing (pre-processing) of the photosensitive drum 108 is completed, the platen glass 10
The original surface of the original placed on the first scanning mirror 106 is illuminated by an illumination lamp integrally formed with the first scanning mirror 106. The reflected light of the original passes through the scanning mirrors 103 and 104 and passes through the lens 1.
05, the image is formed by the light receiving element inside the lens unit.

The reflected light image from the original is converted into an electric signal by a light receiving element and sent to an image processing unit (not shown). In this image processing unit, predetermined data processing received by the copying machine main body 100 from the user is performed. After the laser section 12
2. The electric signal subjected to the data processing is converted into light by the laser unit 122, reflected by the polygon mirror 123 and the mirror 125, becomes an electrostatic latent image on the photosensitive drum 108, and is visualized by toner. The image is transferred onto a transfer sheet as described later.

The sheets set in the cassette 200 or the manual feed tray 120 are supplied to the sheet supply roller 1.
18, 119, 201 and the intermediate roller 202, the sheet is sent to the photosensitive drum 108 at an accurate timing by the registration roller 107, so that the leading edge of the latent image coincides with the leading edge of the sheet. You.

Thereafter, the photosensitive drum 108 and the roller 110
And the toner image on the drum 108 is transferred onto the sheet. Then, the sheet is separated from the drum 108, guided to the fixing device 112 by the transport belt 111, and the toner image is fixed by pressurizing and heating of the fixing device 112. The sheet on which an image has been formed in this way is guided by the flapper 114 toward the sheet discharge roller 115, and is discharged to the main body 1 of the sheet post-processing apparatus with the print surface up.

On the other hand, in the ADF 300,
Indicates a stacking tray on which the original bundle 302 is set.
For example, in the case of a single-sided original, the lowermost original of the original bundle is separated one by one by a half-moon roller 304 and a separation roller 303, and the paths 311a and 311 are moved to the exposure position of the original table glass 101 by the transport roller 305 and the full-surface belt 306.
After being conveyed via 1b, it is stopped to prepare for the start of the copying operation.

After the copying is completed, the original is sent to the path 311f by the large conveying roller 307 via the path 311d, and is again returned to the bundle 3 by the sheet discharge roller 308.
02 is returned to the upper surface. A recycle lever 309 for detecting one cycle of the original is placed on the upper part of the original bundle at the start of the original feeding, and is dropped by its own weight when the original is sequentially fed and the end of the final original comes off. It is designed to detect circulation.

In the ADF 300, when a double-sided document is used, the document is once guided to paths 311a and 311b to 311c.
Then, by switching the rotatable switching flapper 310, the leading end of the document is guided to the path 311d, and
Then, the sheet is conveyed onto the platen glass 101 by the entire belt 306 through the path 311b, and then stopped. In other words, the original is moved by the conveyance large roller 307 to the paths 311c to 311d.
311b.

Incidentally, a stopper member (not shown) is provided on the upper portion of the main body 1 of the sheet post-processing apparatus. The main body 1 of the sheet post-processing apparatus is connected to the main body 100 of the copying machine by positioning the stopper member on a holding unit (not shown) formed on a side surface of the main body 100 of the copying machine. Further, a folding machine unit or a mounting base 70 is provided below the main body 1 of the sheet post-processing apparatus, and a caster 80 is movably mounted on the mounting base 70.

Therefore, when performing a jam clearance process near the sheet discharge portion of the main body 100 of the copying machine or a jam clearance process at the transfer portion between the main body 1 of the sheet post-processing device and the main body 100 of the copying machine, a stopper (not shown) is used. By rotating the member to release the engagement with the holding portion, and then moving the main body 1 of the sheet post-processing apparatus in the horizontal direction to separate the main body 100 of the copying machine, the operation can be easily performed. Has become.

On the other hand, the sheet on which the image is formed is conveyed to either the main body 1 of the sheet post-processing apparatus or a folding device (not shown) provided inside the mounting table 70 in accordance with the subsequent processing. Has become. That is, when a sheet is processed by the main body 1 of the sheet post-processing apparatus, the upstream end of the first flapper 3 close to the main body 100 of the copying machine shown in FIG. By locating the upstream end of the downstream second flapper 4 in the upward direction, the sheet is sent to the first transport path 6 by the roller pair 5 and further downstream from the first transport path 6. become.

When the sheet is conveyed to the folding device,
By positioning the upstream end of the first flapper 3 in the upward direction as shown in FIG. 2, the sheet is sent to the folding device located at the end of the direction indicated by the dashed arrow in FIG.

In FIG. 2, reference numeral 8 indicates a second transport path (buffer path), reference numeral 9 indicates a buffer roller, reference numerals 14, 15, and 16 indicate buffer rollers, and reference numerals 10, 11, 12, and Reference numeral 13 denotes a sheet detection sensor. The sheet detection sensors 10, 11, 1
Reference numerals 2 and 13 perform detection of a passing sheet, detection of a staying sheet, and the like.

Reference numeral 17 denotes a first discharge roller, reference numeral 18 denotes a press roller, and reference numeral 19 denotes a discharge alignment belt. The discharge alignment belt 19 includes a first discharge roller 17 and
An endless rib (not shown) is provided near the central portion inside the belt as a measure to prevent the belt from coming off, and is rotated by engaging with the first discharge roller 17. I have.

Inside the discharge matching belt 19, a belt roller 61 for moving the belt is disposed. The discharge alignment belt 19 is swung by a belt moving plate 62 that reciprocates by a driving source (not shown). The belt moving plate 62 and the belt rollers 61, 61
By a, a moving means for forcibly deforming the discharge alignment belt 19 is configured.

When the tray unit 26 (see FIG. 1) stacks and moves the sheets, it rises and closes the hatched portion indicated by F in FIG. Can be prevented from falling,
When the sheet is discharged to the first tray 24, the sheet is moved below the second discharge roller 32 so as not to hinder the discharge of the sheet.

In FIG. 2, the width shift plate 21 is adapted to adjust the width of the sheet. Reference numeral 20 indicates an alignment butting member that regulates the rear end of the sheet. The alignment abutting member 20 can take a home position when sheets are sequentially stacked on the staple tray 38 and a retracted position when the stapler (binding means) 22 moves forward and backward. When the position of the stapler 22 is changed, the alignment butting member 20 having the same phase as that of the stapler 22 can be rotated to the position shown by the broken line and retracted.

By the way, in the present embodiment, the alignment of the sheet in the width direction is performed by using the width shifting plate 21 shown in FIGS.
Done by Further, the stapler 22 performs stapling by moving in a range indicated by an arrow in FIG. 3 so that the sheet can be bound at two places, the front side is bound at one place, and the back side is bound at one place. Although the description of the operation of the stapler 22 is omitted, the stapler 22 itself has almost the same configuration as that of a commercially available electric (solenoid) or motor-driven automatic stapling apparatus. The sheets are bound. 3 and 4, reference numeral 21a indicates an alignment reference plate.

In FIG. 1, reference numerals 24 and 25 denote first and second trays for stacking sheets discharged from a discharge port 50 formed in the side wall 1a of the main body 1 of the sheet post-processing apparatus. . Reference numeral 26 denotes a tray unit to which the first and second trays 24 and 25 are attached in the up-down direction and inclined to the main body 1 side. The tray unit 26 is provided on the side wall surface 1a of the main body 1 of the sheet post-processing apparatus.
And is vertically movable by a drive source (not shown) built in a lower portion thereof.

On the side wall surface 1a of the main body 1 of the sheet post-processing apparatus, the sheet discharged on contact with the inclined ends of the sheets stacked on the first and second trays 24 and 25 flows backward to the upstream side. Upper and lower regulating members (hereinafter, referred to as “upper snow guide” and “lower snow guide”) 27, 2
7a is provided.

In FIG. 5, the swinging guide 31 rotatably holds the movable discharge roller 33, and rotates the cam 35 shown in FIG. As shown in FIG. 5, the movable discharge roller 33 is pressed against the second discharge roller 32 by swinging downward about the swing shaft 31a as a fulcrum.

The swing guide 31 swings upward so as to separate the movable discharge roller 33 from the second discharge roller 32 in a staple mode, which will be described later, to move the two rollers 32, 33 from a state in which the sheet can be carried out. The sheet plays a role of a switching unit for setting the sheet unloadable state.

5 and 7, the stopper 30
Rotates around the rotation shaft 30a when the tray moves,
As shown in FIG. 7, when the first tray 24 passes through the discharge port 50 while being locked by being fitted into the groove portion 34 a of the rising saw blade shutter 34 and closing the discharge port 50, the first tray 24 The stacked sheets S are prevented from flowing back to the discharge port 50.

When the sheet is discharged, the stopper 30 is rotated in the Y direction shown in FIG.
In the staple mode, which will be described later, the lock is rotated in the direction to release the discharge port 50, as in the swing guide 31, as shown in FIG. I have. In the same figure, reference numeral 271 indicates a rib formed on the upper slender guide 27.

Next, the operation of the sheet post-processing apparatus thus configured will be described. When a sheet is discharged without performing stapling, the first and second trays 24 and 25 are directly discharged. FIG. 9 shows the first tray 24
2 shows a case where the sheet is discharged.

When the non-staple mode is selected by the user, the swing guide 31 is moved by the cam 35 (see FIG. 6) to a position where the movable discharge roller 33 is pressed against the second discharge roller 33 as shown in FIG. Rocks. Also,
The scraper shutter 34 is located below the second discharge roller 32 so as not to hinder sheet discharge.

In this state, the sheet discharged from the main body 100 of the copying machine passes through the transport path 6 shown in FIG. 2 to the roller pairs 5 and 17, and is further discharged downstream by the roller pairs 5 and 17. After that, the paper is directed toward the first tray 24 by the swing guide 31, discharged from the discharge port 50 via the discharge rollers 32 and 33, and sequentially stacked on the first tray 24. Alternatively, depending on the size, the sheets are sequentially stacked on the first tray 24 discharged from the discharge port 50 through the discharge rollers 32 and 33 through the roller rows 14, 16 and 18 through the transport path 8.

When a large number of normal sheets S are to be taken, first, first and second sensors 24a and 25a (see FIG. 1) installed in the first and second trays 24 and 25 are used. After confirming that no sheets remain on the trays 24 and 25, the tray unit 26 moves to a predetermined position for receiving the first sheet of the first tray 24.

Further, when the number of stacked sheets reaches a certain number, the tray unit 26 (see FIG. 1) is set such that the upper surface of the stacked sheets is substantially the same as the surface receiving the first sheet. Descend to the position. When the above operation is repeated and it is detected that the maximum amount of sheets is loaded in the tray, a stop signal is issued to the main body 100 of the copying machine,
Pause sheet ejection.

Next, the tray unit 26 is lowered to a position where the first sheet on the second tray 25 is set so as to stack the sheets on the second tray 25. Thereafter, the copying operation is restarted by the main body 100 of the copying machine, and the stacking of sheets is restarted. Thereafter, the same operation as described above is repeated until the second tray 25 is fully loaded.

In this embodiment, the main body 100 of the copying machine is of a digital type, and the main body 100 of such a copying machine includes a scanner unit for reading an image of a document and a printer unit for reproducing the image. It consists of
Each can operate independently. In other words, the scanner unit irradiates the original with a lamp and decomposes the reflected light into small points (pixels) using a light receiving element and simultaneously converts it into an electric signal (photoelectric conversion) according to the density of the original. Based on the electric signal sent from the department,
The drum is irradiated with a laser beam, an electrostatic latent image is formed on the drum, and a copy image is formed through a developer, transfer, and fixing.

By connecting an interface 500 to a digital copying machine as shown in FIG. 1, an original signal read by the scanner unit is transferred to another facsimile machine 501, and conversely, an electric signal received from another facsimile machine 501 is received. Can be sent to the printer unit through the interface 500 to print out the image on a sheet.

Similarly, an image signal received from a computer device 502 such as a personal computer is transmitted to the interface 50.
0 to a printer unit, copy the image to a sheet, or read an image read by a scanner unit through an interface 500.
And can be imported to a personal computer.

As described above, in the current digital copying machine, the original sent from the ADF 300 or the original
1. Not only is the original placed on top read and copied, but also through the interface 500,
It can be used as a facsimile or as a printer for a personal computer.

By the way, in order to use the present apparatus 100 in this way, sheets are sorted into different trays and stacked, or depending on the user's request, each tray is numbered, and the user's request is given. It is necessary to load the sheets on the tray.

For this reason, in the present embodiment, for example, the output sheet in the copy mode is
Output sheets from a personal computer are stacked on the second tray 25.

Next, the operation of discharging sheets to each tray will be described. First, when stacking sheets S in the copy mode after receiving a certain number of output sheets from the personal computer shown in FIG.
4 will be described. When the first tray 25 is used after receiving a certain number of output sheets from the personal computer, the tray unit 26 moves down to a position where the first sheet of the first tray 24 is received. The operation is the same as that in the copy mode except that the number of sheets stacked in the tray is lowered even if it is not the maximum.

Next, a case where output sheets of a personal computer or the like are stacked in a state where a certain number of output sheets in the copy mode are received on the first tray 24, that is, a case where the first tray 24 is used will be described.

While the sheets are stacked on the first tray 24, the tray unit 26 is moved up to stack the sheets on the second tray 25. At this time, in order to prevent the sheet S from entering the space indicated by the hatched portion F in FIG.
As shown in (a), the sunroof shutter 34 rises and closes the space of the portion F, so that the first tray 24 can move upward while the sheets S are stacked. The sheet abutting surface of the saw blade shutter 34 has a rib shape so that the sheet S can slide easily, similarly to the sheet abutting surface 31b of the swing guide 31 (see FIG. 6) and the lower snow saw guide 27a.

With such a configuration, the sheet S can pass through the discharge port 50 without flowing backward, so that the first tray 24 moves upward while the sheets S are stacked. It becomes possible. Also,
By using the sheet abutting surface 31b of the swing guide 31 as a part of the upper sliding guide 27, the interval between the trays can be reduced, and the tray unit 26 can be downsized.

The operation described above is an operation in the case of moving from the second tray 25 to the first tray 24, but is the same even when starting from any tray.

Next, the stapling operation of the sheet post-processing apparatus will be described. First, at the time of staple sorting in which copying is performed by performing stapling, the first and second trays 2 are used.
First, the sheets are stacked on the staple tray 38 shown in FIG.

When the staple sort mode is selected by the user, the sheet post-processing apparatus operates as follows.

FIG. 9 is a diagram showing a state where the first sheet is stacked on the staple tray. First,
When the first sheet is conveyed, as shown in FIG. 9A, the swing guide 31 is at the lowered position, and the sheet S is transferred to the first discharge roller 17 and the second discharge roller 32. Is transported leftward in FIG.

The trailing end of the sheet S is the discharged sheet detection sensor 1.
FIG. 9B shows a state in which a predetermined time has passed after passing through No. 3 and the sheet has further advanced downstream from the discharge matching belt 19. In this state, the second discharge roller 32 stops. Further, the sheet S stops at a position advanced by a predetermined amount from the discharge alignment belt 19 rotating together with the first discharge roller 17.

Next, the sheet S on the staple tray 38
FIG. 9 (c) shows a state in which is forcibly pulled back to the upstream side. Here, the second sheet discharge roller 32 rotates in the direction of arrow G, and pulls the sheet S upstream in the transport direction.

Further, as the rear end of the sheet S reaches a position where the trailing edge contacts the discharge alignment belt 19, the swing guide 31
After ascending to the position as shown in FIG. 9 (d), the position is detected by a sensor (not shown) and stopped.

The staple tray 38 is mounted inside the main body 1 of the sheet post-processing apparatus at an angle such that the sheets S are stacked on the staple tray 38 by its own weight. Further, the first tray 24 is positioned above the non-staple mode so as to support the rear end of the sheet S and assist the sheet S to return to the upstream side in the discharge direction.

On the other hand, as shown in the figure, the sheet S discharged onto the staple tray 38 is
8 and the position of the first tray 24 are increased to assist in sloping down its own weight to the upstream side in the discharge direction, but further rotated in the direction of the arrow in synchronization with the first discharge roller 17. The discharge alignment belt 19 urges the staple tray 38 in the upstream direction.

Therefore, the sheet S is placed on the alignment
It is aligned in a direction perpendicular to the discharge direction by striking zero. Further, in the widthwise alignment of the sheet S, the width shift plate 21 (see FIGS. 3 and 4) starts operating a predetermined time after the sheet S falls on the staple tray 38 and hits the alignment abutting member 20. This is performed by moving the sheet S from the back side of the main body toward the near side by a predetermined dimension rather than the width dimension of the sheet S, and aligning the sheet S with the near side.

Here, the discharge matching belt 19 is made of a rubber member having flexibility (elasticity) and a high friction coefficient. Therefore, when the sheet S shown in FIG. 10A is rotated in the direction of the arrow to align the sheet S, the sheet S bends due to its elasticity and is deformed to the upstream side in the sheet discharging direction as shown in FIG. I do. Therefore, the rear end of the sheet S that is conveyed next falls at the downstream position 19 a of the deformed discharge alignment belt 19.

FIG. 10A is a view showing a state immediately after the sheet S in the staple mode has been discharged to the staple tray 38. In FIG. 10A, the paddle 71
Is formed of an elastically deformable member and stops at a position above the swing guide 31 so as not to hinder the discharge of the sheet. When the sheet S is discharged onto the staple tray 38, one rotation operation is performed. Discharge alignment belt 1 at the rear end of S
The pull-back operation is performed up to the nip point 9. Paddle 71
Rotates intermittently. Further, the sheet S that has entered the nip point of the discharge alignment belt 19 is conveyed in the direction of the discharge alignment belt 19 and the alignment contact member 20 (see FIG. 9) by its own weight.

The belt roller 61 is provided on the belt moving plate 62, is disposed inside the discharge alignment belt 19, and is movable by the belt moving plate 62. The discharge alignment belt 19 is a member having elasticity, and can be easily deformed by the belt rollers 61. Normally, when the discharge roller 17 rotates in the discharge direction to discharge the sheet to the first tray 24, the discharge alignment belt 19 is deformed to the downstream side in the transport direction by its own frictional force (FIG. 10B).
However, by moving the belt moving plate 62 in the direction of the arrow, the belt rollers 61 pull back the discharge alignment belt 19 in the upstream direction.

Therefore, the rear end of the conveyed sheet S falls to a position indicated by reference numeral 19c upstream of the downstream position 19a shown in FIG. Therefore, since the amount of sheet jump is small, it is easy to drop under its own weight.

Further, since the time when the sheet is discharged to the staple tray 38 can be detected by the discharged sheet detection sensor 13 (FIG. 2), after the sheet is discharged to the staple tray 38, the belt moving plate is moved within a predetermined time. 62 is moved to the position shown in FIG.
1, 61a is moved in the downstream direction. Here, with respect to the belt roller 61 rotatably supported by the belt moving plate 62, the small belt roller 61a is also rotatably supported by the belt moving plate 62 so as to sandwich the discharge alignment belt 19. And belt rollers 61 with respect to the belt moving plate 62,
The small belt rollers 61a also do not hinder the rotation of the discharge alignment belt 19. Therefore, the discharge matching belt 19
Is forcibly pushed back downstream.

Here, the contact point 19d between the discharge alignment belt 19 and the sheet S is on the downstream side of the upstream position 19c. For this reason, even if the sheet S does not slide down on the staple tray 38, the discharge alignment belt 19 can draw the sheet S in the upstream direction.

After the discharge alignment belt 19 abuts the sheet S against the alignment abutting member 20 to perform alignment in the conveyance direction by the above operation, the width shift plate 21 (see FIG. 3) moves the sheet S to the alignment reference plate. It moves in the direction of 21a and aligns.
At this time, the sheet is a regenerated sheet with an unstable friction coefficient, a sheet that is easily charged by static electricity,
Alternatively, in the case of a sheet having a size longer in the conveying direction than the sheet in the width direction, the width shift plate 21 is stacked on the staple tray 38 due to dimensional restrictions of the main body 1 of the sheet post-processing apparatus. The pressing operation can be performed only at the rear end portion of the sheet near the alignment butting member 20.
For this reason, the sheet rarely moves and is aligned with the alignment abutting member 20 while maintaining the parallelism. As a result, the sheet may be aligned with the alignment abutment member 20 in an oblique state during the alignment operation in the sheet width direction. In such a case, when the sheets are stapled, misalignment occurs. Therefore, when the alignment operation in the sheet conveying direction is performed again by the paddle 71, the sheet can be reliably abutted against the alignment abutting member 20 and aligned.

The above operation is repeated until the second and subsequent sheets S are stacked on the staple tray 38 by the number set by the user. When the number of sheets set by the user is aligned on the staple tray 38, the swing guide 31 moves down, and the movable discharge roller 33
And the discharge roller 32 sandwich the sheet bundle. Thereafter, the stapler operates to perform an operation of stapling to a position set by the user.

FIG. 9E shows the state at this time. Further, after the stapling is completed, the discharge roller 32 rotates in a direction for conveying the sheet to the downstream side, and the stapled sheet bundle is stacked on the stacking tray 24.

The main body 1 of the sheet post-processing apparatus manages the size information of the sheet conveyed from the main body 100 of the copying machine and the discharged sheet detecting means 13 for counting the number of sheets stacked on the staple tray 38. Since the control unit 510 is provided, it is possible to switch whether or not to perform the alignment operation in the transport direction by the paddle 71 after the width adjustment based on the size and the number of sheets stacked on the staple tray.

Specifically, when the aligning operation in the transport direction is performed by the paddle 71 after the width adjustment, the staple tray 3
8 requires a longer processing time for the sheets to be stacked than in the case where the processing is not performed. Depending on the sheet processing speed of the main body 100 of the copying machine, when the mode of stacking on the staple tray 38 is selected, the interval of sheet discharge of the main body 100 of the copying machine is increased, and a waiting time is required.

Therefore, a small size (for example, A
4, B55) can be stacked on the staple tray 38 without any problem without performing the alignment operation in the transport direction after the width adjustment. For this reason, the processing time of the main body 100 of the copying machine is prioritized, and there is no need to perform the alignment operation in the transport direction after the width adjustment.

However, after a sheet of large size (A3, B4, etc.) is discharged onto the staple tray 38, the next sheet is discharged from the main body 100 of the copying machine until the next sheet is discharged from the main body 100 of the copying machine. Since time is required for processing inside the sheet, there is a margin in the processing time of the sheet in the transport direction, and the dimension in the transport direction is longer than the dimension in the width direction of the sheet. Further, due to the dimensional restrictions of the sheet post-processing device, the width shift plate 21 can only perform the pressing operation at the rear end near the alignment butting member 20 of the sheets stacked on the staple tray 38. For these reasons, a large-sized (A3, B4, etc.) sheet is rarely moved and aligned while maintaining parallelism with the alignment abutting member 20 during the alignment operation in the sheet width direction. The sheet may be aligned with the aligning butting member 20 in a state where the sheet is inclined. The control unit 510 (see FIG. 1) controls the rotation of the paddle 71 based on the sheet size information,
The alignment operation in the sheet conveying direction is performed again. by this,
The large-sized sheets (A3, B4, etc.) are reliably pressed against the alignment abutting member 20, and the alignment of the ends of the sheets in the transport direction is reliably performed.

Further, a large-sized sheet (A3, B4, etc.) has a dimension in the conveying direction longer than the dimension in the width direction of the sheet. Further, the width shift plate 21 can press only the rear end portion of the sheet stacked on the staple tray 38 in the vicinity of the aligning butting member 20 due to dimensional restrictions of the sheet post-processing apparatus. For these reasons, if the number of sheets stacked on the staple tray 38 is large during the alignment operation in the width direction of the sheets, the sheets may be aligned and abutted depending on the curl of the previously stacked sheets and the conditions of the friction coefficient. The sheet is rarely moved and aligned while maintaining the parallelism with the member 20, and the sheet may be aligned with the alignment abutting member 20 in an oblique state. Therefore, the control unit (see FIG. 1) 510 controls the rotation of the paddle 71 based on the number of stacked sheets, and performs the alignment operation in the sheet conveying direction again. Thereby, the large size (A
3, B4, etc.) are reliably pressed against the alignment abutting member 20, and the alignment of the sheet conveying direction end is reliably performed.

Further, according to the combination of the sheet size information and the information of the number of sheets stacked on the staple tray 38, whether or not the paddle 71 performs the transport direction alignment operation after the width direction alignment operation is performed. May be determined.

Further, when binding the sheet bundle, the sheets are sequentially discharged from the main body 100 of the copying machine.
The sheet post-processing apparatus 600 performs an operation in which the first sheet of the discharge sheet of the next job is retained in the main body 1 of the sheet post-processing apparatus, and is discharged while being superimposed on the second sheet.

The operation will be described with reference to FIG. FIG. 12A illustrates a state where the sheet S has begun to enter the main body 1 of the sheet post-processing apparatus. Copier body 10
0, the first sheet S1 discharged from flapper 3,
4 is inclined downward, so that the buffer path 8
Sent to Sheet S1 sent to buffer path 8
Is wound around the buffer roller 9 and sent in the direction indicated by the arrow. Here, the flapper 39 is such that the sheet S1 is the roller 1
5 so as to be fed in the direction of 5
And stops at the state as shown in FIG.

Then, when the second sheet S2 enters, the buffer roller 9 starts rotating, and FIG.
As shown in (c), the first sheet S1 and the second sheet S2 are conveyed in an overlapping manner. Further, when the rear end of the first sheet S1 passes through the flapper 39, the flapper 39 rotates so that the sheet S is fed in the direction of the discharge rollers 17 and 18 as shown in FIG. The sheets are discharged onto the staple tray 38 with the two sheets stacked.

By performing the above operations, the stapler 22
During the stapling operation, the discharge rollers 17, 1
8, the sheet S is not discharged, the stapling operation can be performed, and the operation of the main body 100 of the copying machine does not stop.

In order to obtain more time for performing the stapling operation, the third or more sheets S
Can also be wound.

{Sheet Standby Position for Overlap Ejection Control} As described above, if a plurality of sheets are ejected in a stacked manner, the sheet post-processing apparatus 600 causes the preceding sheet waiting in the buffer path 8 to wait. It is necessary to convey S1 and the succeeding sheet S2 discharged from the main body 100 of the copying machine so that the deviation amount between the leading ends of the sheets is constant. For this reason, the control unit 510 determines that the subsequent sheet S2 is the entrance sensor 1 shown in FIG.
0, or after a predetermined clock elapses after the succeeding sheet S2 has passed the entrance sensor 10, the rotation of the buffer roller 9 is started so that the amount of deviation between the leading ends of the preceding sheet S1 and the succeeding sheet S2 is constant. ing.

However, the conveying speed of the succeeding sheet S2 discharged from the main body 100 of the copying machine is changed depending on the image forming mode, the type of the sheet, and the like. On the other hand, the control unit 510 needs to change the activation timing of the buffer roller 9 in order to keep the amount of deviation between the leading ends of the preceding sheet S1 and the succeeding sheet S2 constant.

Therefore, the conveying speed of the succeeding sheet S2 according to the image forming mode and the type of sheet is controlled by the main body 100 of the copying machine.
The control unit 51
Numeral 0 controls the rotation of the buffer roller 9 to change the feeding timing of the preceding sheet S1 to be stopped in the buffer path 8 according to the transport speed of the succeeding sheet S2.

The control unit 510 holds the preceding sheet S1 at a fixed position in the buffer path 8, and when the succeeding sheet S2 is conveyed at a high speed, immediately after the succeeding sheet S2 passes through the entrance sensor 10, The roller 9 is started. When the conveying speed of the succeeding sheet S2 is low, the buffer roller 9 is started after a lapse of a predetermined time after the succeeding sheet S2 passes through the entrance sensor 10. In this manner, the preceding sheet S is determined according to the conveyance speed of the succeeding sheet S2.
By changing the conveyance start timing of No. 1, it is possible to make the amount of deviation of the leading ends of both sheets S1 and S2 constant.

Note that the conveying speed of the succeeding sheet S2 is controlled by the main body 100 of the copying machine as described above. However, generally, the succeeding sheet S2 is conveyed at the same speed as the preceding sheet S1. Therefore, the transport speed of the succeeding sheet S2 may be detected by detecting the transport speed of the preceding sheet S1.

Although the above-described overlap discharge control is effective when performing a sort process or a process of binding a sheet bundle, the overlap discharge control may be performed in other cases. Conversely, it is naturally possible to set so as not to perform the overlap discharge control.

The sheet post-processing apparatus 600 of the above embodiment
The sheet S discharged to the staple tray (sheet stacking means) 38 by the discharge rollers 17 and 18
The paddle (first sheet conveyance alignment means, rotating member) 71 is pulled back to the nip point between the discharge alignment belt (second sheet conveyance alignment means, rotator) 19 and the staple tray 38, and then the discharge alignment belt 19 The sheet is abutted against the alignment abutting member (sheet receiving means) 20 by a frictional force, and the transport direction is aligned. Then, the sheet is pressed against an alignment reference plate (sheet width aligning means) 21a by a width shifting plate (sheet width aligning means) 21 to perform an alignment operation in the width direction. At this time, when the sheet is a sheet having a large coefficient of friction, a sheet which is easily charged with static electricity, or a sheet having a size in the conveying direction longer than the sheet in the width direction, or when the number of stacked sheets is large, It is difficult for the aligned sheet to move in parallel along the alignment abutting member 20, and the alignment in the sheet conveyance direction may be disturbed. In such a case, the control unit (control means) 150 rotates the paddle 17 again, presses the sheet against the aligning butting member 20, and performs the aligning operation in the sheet conveying direction. The number of stacked sheets and the length of the sheet are detected by a sensor (not shown).

As a result, the sheet post-processing apparatus 600 can be used for a regenerated sheet having an unstable coefficient of friction, a sheet which is liable to stick due to electrification of static electricity, or a sheet having a size longer in the conveying direction than the sheet in the width direction. Even if the sheet is obliquely aligned with the alignment abutting member during the alignment operation in the width direction, since the paddle 17 performs the alignment operation in the transport direction again, the alignment in the sheet transport direction is performed. Can be performed reliably. If the ends of the sheet in the conveying direction are aligned, the stapler (sheet binding means) 2
2 can reliably perform the sheet binding operation.

[0102]

According to the sheet post-processing apparatus of the present invention, even if the sheet has a large coefficient of friction, a sheet which is easily charged with static electricity, or a sheet whose size in the conveyance direction is longer than the width of the sheet. The ends in the transport direction can be reliably aligned.

Further, since the image forming apparatus of the present invention is provided with the above-mentioned sheet post-processing device capable of reliably aligning the end portions in the sheet conveying direction, the end portions of the sheet bundle do not become uneven. Thus, the end portion is not damaged.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view of a copying machine which is an image forming apparatus provided with a sheet post-processing apparatus according to the present invention in a main body.

FIG. 2 is a schematic front sectional view of the sheet post-processing apparatus of FIG.

FIG. 3 is a plan view of a staple tray unit of FIG. 2;

FIG. 4 is a side view of the staple tray of FIG. 2;

FIG. 5 is an enlarged front sectional view of a main part of the sheet post-processing apparatus.

FIG. 6 is a perspective view of a swing guide section of the sheet post-processing apparatus.

FIG. 7 is a diagram for explaining the operation of a saw shutter of the sheet post-processing apparatus. FIG. 3A is a diagram illustrating a state in which a sheet shutter blocks a sheet discharge unit. FIG. 5B is a diagram illustrating a state in which the sheet shutter opens a sheet discharge unit.

FIG. 8 is an operation diagram for discharging sheets to a staple tray in a staple mode.

FIG. 9 is a diagram illustrating an operation of discharging a sheet to a staple tray in a staple mode of the sheet post-processing apparatus. FIG. 7A is an operation diagram during discharge of a sheet to a staple tray. FIG. 4B is a diagram illustrating a state where the sheet has dropped onto the staple tray. FIG. 9C is an operation diagram when the sheet is drawn toward the alignment butting member. FIG. 6D is a diagram in which the swing guide is raised by abutting the sheet against the alignment contact member. (E) is a diagram showing a state in which sheets have been stacked.

FIG. 10 is an operation diagram of a discharge alignment belt that aligns sheets on a staple tray of the sheet post-processing apparatus. FIG. 7A is a diagram illustrating a state immediately after a sheet in a staple mode is discharged to a staple tray. FIG. 5B is a diagram in which the discharge alignment belt is deformed downstream in the sheet conveying direction by its own frictional force.

FIG. 11 is an explanatory diagram illustrating an operation of discharging a sheet bundle on a staple tray. (A) is a state diagram of the start of sheet bundle discharge. FIG. 7B is a diagram illustrating a state in which a sheet bundle is being discharged. FIG. 6C is a state diagram in which the discharge of the sheet bundle is completed.

FIG. 12 is a diagram for explaining an operation of accumulating a plurality of sheets in a main body of the sheet post-processing apparatus and discharging the sheets to a staple tray. FIG. 3A is a diagram illustrating a state in which a sheet has begun to enter the main body of the sheet post-processing apparatus. FIG. 4B is a diagram illustrating a state in which a preceding sheet is held in a buffer path. (C) is a diagram illustrating a state where a subsequent sheet has begun to be fed into a buffer path. (D) is a diagram showing a state in which two sheets are stacked and started to be discharged to a staple tray.

[Explanation of symbols]

S Sheet 1 Main Body of Sheet Post-Processing Apparatus 17 Discharge Roller 18 Press Roller 19 Discharge Alignment Belt (Second Sheet Transport Alignment Means Second Sheet Transport Alignment Means, Rotating Body) 20 Alignment Abutment Member (Sheet Receiving Means) 21 Width Shift plate (sheet width matching means) 21a Alignment reference plate (sheet width matching means) 22 Stapler (sheet binding means) 38 Staple tray (sheet stacking means) 71 Paddle (first sheet transport matching means, rotating member) 100 Copy machine Main body (image forming apparatus main body) 108 photosensitive drum (image forming section) 150 control section (alignment control means) 600 sheet post-processing apparatus 700 copying machine (image forming apparatus)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Yamada 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 3F054 AA01 AC02 AC03 AC05 BA04 BG04 BG11 BH13 BH14 DA01 3F108 GA02 GA03 GA04 GB01 HA02 HA36 HA39

Claims (8)

[Claims] 1. A sheet stacking unit on which discharged sheets are stacked, a sheet receiving unit for receiving an upstream end of the sheet stacked on the sheet stacking unit in a conveying direction, and a sheet stacking unit on the sheet stacking unit. A first sheet transport aligning unit that transports the sheet toward the sheet receiving unit; and a sheet transport direction in which the sheet transported by the first sheet transport aligning unit is brought into contact with the sheet receiving unit. Second sheet transport aligning means for aligning an upstream end of the sheet, sheet width aligning means for aligning a sheet bundle stacked on the sheet stacking means in a direction intersecting the sheet conveying direction, Controlling the operation of the sheet transport aligning means to transport the sheet on the sheet stacking means toward the second sheet transport aligning means; Means for controlling the means to bring the sheet into contact with the sheet receiving means to align the end of the sheet in the conveying direction, and then controlling the operation of the sheet width aligning means to align the width of the sheet; And control means for controlling the operation of the first sheet conveyance aligning means again to bring the sheet into contact with the sheet receiving means and aligning the end of the sheet in the conveying direction. Post-processing device. 2. The method according to claim 1, wherein the control unit is configured to perform at least one of a case where a length of the sheet in the conveyance direction is equal to or more than a predetermined length and a case where the sheet stacking unit is stacked with a predetermined number of sheets or more. 2. The sheet post-processing apparatus according to claim 1, wherein the first sheet conveying and aligning means is operated again. 3. The sheet post-processing apparatus according to claim 1, wherein the first sheet conveyance aligning means includes an elastically deformable rotating member that rotates intermittently. 4. The sheet post-processing apparatus according to claim 1, wherein said second sheet conveyance aligning means has an elastically deformable rotating body. 5. The first sheet conveyance alignment means has an intermittently rotating elastically deformable rotating member, the second sheet conveyance alignment means has an elastically deformable rotating body, and the rotating member is The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus is disposed above the rotating body. 6. The apparatus according to claim 4, wherein the rotating body is rotatable in a direction in which the sheet stacked on the sheet stacking unit is conveyed away from the sheet receiving unit and discharged. 6. The sheet post-processing apparatus according to 5. 7. A method according to claim 1, further comprising sheet binding means for binding a sheet bundle loaded on said sheet loading means.
Or the sheet post-processing apparatus according to 2 or 6. 8. The sheet post-processing apparatus according to claim 1, wherein an image forming unit that forms an image on a sheet, and the sheet on which the image is formed by the image forming unit are aligned. An image forming apparatus comprising: